JPS6110980Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the connection structure between the body and the head of a laminated tube consisting of a body made of a laminated material and a head made of plastic.

Single-layer plastic tubes are well known;
Its structure is shown in Figures 1 and 2. FIG. 1 is a front view of a plastic tube with a single layer body, and FIG. 2 is an enlarged partial sectional view of section A of FIG. 1st, 2nd
In the figure, the end of the body part 1 is inserted into a head injection mold by a conventional method and gently bent inward along the inner surface of the mold, resulting in an inwardly bent part 2 having a uniform width around the entire circumference.
The lower end 7 of the umbrella-shaped inclined wall 6 of the head 5 injection-molded in the head injection mold is welded to the inner surface of the inner bent portion 2 during the molding, and the lower end 7 of the umbrella-shaped inclined wall 6 of the head 5 is welded to the inner surface of the inner bent portion 2. The parts are combined.

The outer surface 8 of the inclined wall 6 is flush with the outer surface 3 of the inner bend 2 of the body 1, and is flush with the end surface 4 of the inner bend 2.
is covered with an inclined wall 6 and welded to it. This structure of connecting the body and head of a single-layer tube is also applied to a laminated plastic tube having a laminated body (a body made of a laminated material made of two or more layers).

The inwardly curved part of the body described above is formed by narrowing the cylindrical wall inward, so stress is constantly acting on this part to restore it to its original cylindrical shape. There is. Therefore, in the case of a laminated body, if the adhesive force between each layer of the body and the adhesive force between the body and the head is smaller than the residual stress, the difference between the layers of the body and the head, and between the layers of the body. Peeling occurs. For example, the body has three layers: an outer layer (polyethylene), an intermediate layer (vinylidene chloride), and an inner layer (polyethylene).
The head is made of polyethylene, and as shown in FIG. By injection molding the head part and welding the head part 30 to the inner surface 26 of the inner bending part, even if the width (vertical and diametrical width) is shallow during the inner bending, If the width is such that the circumferential undulations or diametrical wrinkles of the bent portion 24 disappear, the residual stress will be greater than the adhesive force, and peeling will occur between the inner layer and the intermediate layer, which have the weakest adhesive force. do. This will be discussed in detail below.

In FIG. 3, the laminated body 20 consists of a vinylidene chloride intermediate layer 21, a polyethylene outer layer 22, and a polyethylene inner layer 23, with an adhesive (not shown) interposed between each layer. The open end of the body portion 20 is formed into an inwardly bent portion 24 as shown.

The head 30 is a single layer of polyethylene, and the lower end 32 of its sloped wall 31 is welded to the inner surface 26 of the inner bend 24 of the body 20. The outer surface 33 of the inclined wall 31 is flush with the outer surface 25 of the inward bend of the body. The end face of the body 20 is covered with a head.

In this joint structure, since the inner layer 23 of the body is made of the same resin as the head, the inner layer 23 of the body is made of the same resin as the head, the inner surface 26 and the end 27.
It is well welded. However, the intermediate layer 21 and the outer layer 22 are joined only at the head and end surfaces 28 and 29 thereof.

Since the adhesive force between the inner layer and the intermediate layer is weak, and the vinylidene chloride of the intermediate layer has high rigidity (therefore, the residual stress is large), the outer layer and the intermediate layer peel off from the inner layer and the head, as shown in the figure. It will come to the position shown by the two-dot chain line. When this peeling occurs, the tube loses its marketability. The present invention provides a joint structure between the body and the head that prevents this separation.

The present invention consists of a body made of a laminated material and a head made of plastic, and the ends of the body are bent inward, and the inward bend of uniform width forms the lower end of the umbrella-shaped inclined wall of the head. In the laminated tube that is polymerized and welded to
The width of the inwardly curved portion is a width that does not cause waving after the welding, and the umbrella-shaped inclined wall of the head is composed of an inner layer and an outer layer, and at least a part of the inwardly curved portion is a width that does not cause undulation after the welding. an outer layer, the inner surface of the inner bend is welded to the inner layer, the inner and outer layers are welded to each other above the inner bend that is welded to the inner layer, and the outer layer is welded to the inner layer. This is a joint structure between the body and the head of a laminated tube, characterized in that the layer covers the entire circumference up to the point where the inner bend begins to bend.

An example of the present invention will be explained with reference to FIGS. 4 and 5.

FIG. 4 is a sectional view of the vicinity of the joint of a plastic tube having the body and head joint structure of the present invention, and FIG. 5 is an enlarged view of the joint.

4 and 5, 50 is a laminated trunk, 70 is a head, and the trunk 50 includes an intermediate layer 51, an outer layer 52, an inner layer 5
3 (in FIG. 4, the intermediate layer, inner layer, and outer layer are not shown, and are simply shown as one layer), and the umbrella-shaped inclined wall 73 of the head is located inside the inwardly curved portion 54 of the torso. It is made up of an inner layer 71 which is located outside the inner bending portion 54 and an outer layer 72 which is located outside the inwardly bent portion 54.

In this specific example, the inner layer 71 constitutes most of the umbrella-shaped inclined wall 73, and the outer layer 72 constitutes the inner layer 7.
1 , the outer surface 74 of the outer layer 72 is flush with the outer surface 76 of the inner layer 71 . The inwardly bent portion 54 of the body portion 50 overlaps and is welded to the lower end portion 75 of the inner layer 71 of the umbrella-shaped inclined wall 73 of the head portion 70 (the inwardly bent portion 54 rests on the lower end portion 75). The outer layer 72 is superimposed and welded to the inner layer 71 of the umbrella-shaped inclined wall above the welded inwardly bent portion 54, and extends to the vicinity of the bending start point 77 of the inwardly bent portion 54. Inner curved part 54 at the circumference
is covered.

Note that the width w of the inner bent portion 54 (in the present invention, the “width of the inner bent portion” refers to the width of the outer circumferential surface 55 of the barrel perpendicular to the barrel axis and the inner circumferential surface of the barrel (in more detail), as shown in FIG. In other words, the inner circumferential surface of the body inner layer 53 (meaning the width in the diametrical direction and perpendicular to the body axis) with the tip 56 is the width when the end of the body made of laminated material is inserted into the head molding die. When the head is molded using the mold, the inner layer of the umbrella-shaped inclined wall of the head is welded to the inner bend on the inner surface of the inner bend and the entire circumference, and then to the inner bend. This is the width without any waving in the circumferential direction.

In this specific example, the middle layer of the body is made of nylon,
The inner and outer layers are made of modified polyethylene, the head is the inner layer,
Both outer layers were made of modified polyethylene.

The tube of this specific example was manufactured as follows. First, a rectangular laminated sheet with nylon as the middle layer and modified polyethylene as the inner and outer layers is rolled up to form a hollow cylinder, the two edges of the sheets are overlapped, and this overlapping part is heated and pressurized to form the body. The end of the head is inserted into a mold for forming the remainder of the head excluding the outer layer, the end is bent inward to form an inward bend, and the polyethylene is then placed in the mold. The part of the head excluding the outer layer was molded by injection, and at the same time, the lower end of the inner layer of the umbrella-shaped inclined wall of the head was welded to the inner surface of the inwardly bent part.

At this time, if the width w of the inwardly curved portion is sufficiently small compared to the diameter of the body (for example, the diameter of the body is 50 mm),
(approximately 3 mm in the welding process) In the welding process, the inner curved part of the body is heated and softened in the mold together with the inner layer resin of the head umbrella-shaped inclined wall (injected), and the resin is softened along the inner circumferential surface of the mold. Since the diameter is re-molded, there will be no waving after welding.

Next, after joining the inner bent part of the body part and the lower end of the umbrella-shaped inclined wall of the head part as described above, this is taken out from the mold and inserted into the outer layer molding mold to form the head part. Polyethylene is injected onto the inner layer of the umbrella-shaped inclined wall, at a desired location above the inner bend, and over almost the entire surface of the inner bend to form the outer layer of the umbrella-shaped inclined wall. It was welded to the bent part.

In the tube manufactured in this way, since the materials of the opposing layers of the body and the head are made of the same resin, the inner layer of the body, the inner layer of the umbrella-like slope of the head, and the umbrella-like slope of the head are made of the same resin. The inner layer and the outer layer of the umbrella-shaped inclined wall of the head, the outer layer of the umbrella-shaped inclined wall of the head and the outer layer of the body are respectively well welded, and the inwardly curved part of the body is welded to the inner layer of the umbrella-shaped inclined wall of the head. At the same time as welding, the outer layer of the umbrella-shaped inclined wall extends to the vicinity of the bending point of the inwardly curved part and covers the inwardly curved part. Even if the adhesive force is weak and the residual stress in the intermediate layer 51 is greater than the adhesive force, the intermediate layer 51 will not peel off from the inner layer 53.

In the above specific example, the outer layer of the umbrella-shaped inclined wall of the head is provided only at the lower end portion of the umbrella-shaped inclined wall, but it may start from the upper end of the umbrella-shaped inclined wall, or as shown in FIG. Conversely, the outer layer may form most of the umbrella-shaped inclined wall, and the inner layer may be provided only at the inner and lower end portion of the outer layer.

Furthermore, in the above specific example, the inner layer and outer layer of the umbrella-shaped inclined wall of the head and the inner layer and outer layer of the inwardly curved part are made of the same plastic material, and the inwardly curved part has a structure in which both the inner layer and the outer layer are welded. However, the inwardly bent portion and the outer layer do not need to be welded together.

In conventional body parts made of laminated materials and tubes made of plastic, the width of the inwardly curved part of the body part is increased to create a gap between the head part and the inner layer of the body part, as disclosed in, for example, Japanese Utility Model Application No. 1985-8565. To prevent peeling and to absorb the waving in the circumferential direction of the inwardly curved part caused by increasing the width of the inwardly curved end by forming irregularities regularly on the inwardly curved part, the appearance is improved. However, according to the present invention, the width of the inwardly curved part is relatively narrow so that no waving occurs in the circumferential direction after the inwardly curved part and the inner layer of the umbrella-shaped inclined wall of the head are welded. ,
There is no need for a structure for absorbing the corrugation, and the structure is extremely simple compared to conventional laminated tubes, which has the advantage that the manufacturing tool is simple and manufacturing is easy.

Further, according to the present invention, the umbrella-shaped inclined wall of the head part is composed of an inner layer and an outer layer, and the inner layer molded in an inner layer injection mold is attached to the inner surface of the inner curved part. The outer layer molded in an injection mold is then welded to the inner layer during said molding above the inner bend where the outer layer is welded to the inner layer to form the umbrella-shaped inclined wall. The outer layer has a structure that covers the entire circumference of the inner bent portion up to the vicinity of the beginning of the bend. That is, since the umbrella-shaped inclined wall is composed of an inner layer and an outer layer, the inner layer is formed by using a well-known and advantageous technique for welding the molded product to other materials in the mold during injection molding. Welded to the bent end during molding, and after welding the inner layer and the bent end of the body, even if the inner layer occupies a large part of the umbrella-shaped sloped wall or a small part Since the inwardly curved portion maintains its inwardly curved shape even when the inner curve is occupied by The outer layer can then be injection molded to cover the inner bend up to the point where the bend begins.

As described above, the inner surface of the inwardly curved portion of the body is welded to the inner layer of the umbrella-shaped inclined wall, and the outer surface is welded to the inner layer above the inwardly curved portion up to the point where the curve begins. Since it is covered with a layer and sandwiched between an inner layer and an outer layer, even if the width of the inner bend is narrow enough to prevent waving, the inner surface of the inner bend and the inner layer of the umbrella-shaped inclined wall The joint between the body and the head can be maintained without peeling from the welded parts.

Also, since the width of the inwardly curved part can be narrowed, material for the body can be saved, and since there is no undulation in the inwardly curved part, the outer layer is made thicker to obtain a smooth outer surface unlike when there is undulation. In other words, the outer surface is smooth even if the wall is thin, and material can be saved even in the head part.

In addition, when the body and head are connected without an inwardly bent portion, the resistance in the axial direction of the tube is small, and the body and head may be separated.

As described above, according to the present invention, a laminated tube consisting of a body made of laminated material and a head made of plastic is formed by injection molding without wrinkles or unevenness at the joint, and without separation or peeling of the laminated material. Adopting the well-known advantageous means of welding the mold during injection molding, it is inexpensive and
It can be manufactured at high speed and stably, saving material for the body and head.

[Brief explanation of the drawing]

Figure 1 is a front view of a plastic tube with a single layer body, Figure 2 is an enlarged partial cross-sectional view of section A in Figure 1,
Fig. 3 is an enlarged cross-sectional view showing the peeling situation at the inner bending part of the end of the plastic tube with a laminated body, and Fig. 4 is an enlarged sectional view showing the peeling situation near the head/body joint part of the plastic tube with the joint structure of the present invention. Cross-sectional view, FIG. 5 is an enlarged view of section B in FIG. 4, 50... laminated body, 51... intermediate layer, 52...
Outer layer, 53...Inner layer, 54...Body end inwardly bent portion, 70...Head, 71...Head inner layer, 72...
...Outer layer of the head, 75...Lower end of the head.

Claims (1)

[Claims for Utility Model Registration] An umbrella made of a body made of a laminated material and a head made of plastic, formed by bending the ends of the body inward so that the inwardly bent portion of the head has a uniform width. In the laminated tube that is superimposed and welded to the lower end of the shaped inclined wall, the width of the inwardly bent part is such that no waving occurs after the welding, and the umbrella shaped inclined wall of the head part is at least a part of the width. is composed of an inner layer and an outer layer, the inner surface of the inner curve is welded to the inner layer, and the inner and outer layers are welded to each other above the inner curve that is welded to the inner layer. . A structure for connecting a body and a head of a laminated tube, characterized in that the outer layer covers the entire circumference up to a point where the inner bend begins to bend.